The present invention relates to a closure assembly for a tank filler neck, and particularly to a capless closure assembly for a vehicle fuel tank filler neck that operates to close the filler neck automatically as soon as a fuel-dispensing pump nozzle is removed from the filler neck following refueling of the tank. More particularly, the present invention relates to a filler neck closure assembly that cooperates with a fuel-dispensing pump nozzle, which may be connected to a robotic refueling system, to provide an automatic opening and closing mechanism for the filler neck and that functions automatically to vent excess tank pressure and relieve unwanted tank vacuum after refueling is completed.
A removable fuel cap with a sealing gasket is typically used to close the open end of a fuel tank filler neck. After an attendant fills the fuel tank and withdraws the pump nozzle from the filler neck, the fuel cap is attached to the filler neck so that the sealing gasket forms a seal between the fuel cap and the filler neck. Thus, the fuel cap closes the open end of the filler neck to block discharge of liquid fuel and fuel vapor from the fuel tank through the filler neck. Additionally, some fuel caps are provided with pressure-relief and vacuum-relief valves to permit some controlled venting of fuel vapors in the filler neck while the fuel cap is mounted on the filler neck.
It has been observed that fuel caps are often lost or damaged over time and, as a result, the open end of the filler neck might not be closed and sealed in accordance with original equipment specifications during operations of the vehicle. Accordingly, a filler neck configured to xe2x80x9copenxe2x80x9d automatically as a fuel-dispensing pump nozzle is inserted into the filler neck during refueling and xe2x80x9cclosexe2x80x9d automatically once the pump nozzle is withdrawn from the filler neck without requiring an attendant to reattach a fuel cap to the filler neck would be an improvement over many conventional capped filler neck systems. .Although Although conventional fuel caps function to close filler necks in a satisfactory manner, it is thought that a capless filler neck could make vehicle refueling more convenient for consumers because no action other than inserting a pump nozzle into the outer end of the filler neck would be required to begin refueling a vehicle. Advantageously, such a capless filler neck system would be configured in accordance with the present invention to include a liquid fuel and fuel vapor control apparatus.
Filler necks with self-closing closure mechanisms are known in the art. See, for example, U.S. Pat. Nos. 3,938,564 to Jones: 5,056,570 to Harris et al.: and 5,271,438 to Griffin et al. In addition, U.S. Pat. Nos. 5,195,566 to Ott et al.: 4,986,439 to Ott et al.: 4,702,839 to Boehmer et al.: and 4,424,839 to Otani et al., and German document Nos. DE 42 18 287 A1 to Ott and DE 42 43 883 A1 to Soutter all disclose self-closing caps.
A robotic refueling system operates to detect a vehicle arriving at a vehicle-refueling station, locate a fuel tank filler neck in the vehicle, and move a fuel-dispensing pump nozzle automatically into and out of the filler neck at the proper times so that the fuel tank on board the vehicle can be filled with fuel without any manual movement or operation of the pump nozzle by an attendant. For example, U.S. Pat. Nos. 5,238,034 to Corfitsen: 3,642,036 to Ginsburgh, and 3,527, 268 to Ginsburgh: as well as German document No. DE 42 42 243 A1 to Hagele all disclose automatic fueling systems for vehicles provided with filler neck closures suited for use with such systems.
A capless filler neck closure that is configured to control air, vapor, and liquid flow into and out of a fuel tank filler neck and is compatible with robotic refueling systems, yet is configured to be assembled quickly and easily using a minimal number of parts would be an improvement over known filler neck closures. An inexpensive yet effective capless filler neck closure that is reliable, easy to manufacture, and easy to install is needed. This need is expected to grow once robotic refueling systems become widely available. A capless filler neck closure that is configured to open automatically in response to engagement with a moving pump nozzle regardless of whether the pump nozzle is moved manually by an attendant or robotically by a robotic refueling system, and to close automatically after refueling is completed, and that is configured to relieve unwanted excess pressure and vacuum conditions in the tank automatically any time that such conditions develop and the filler neck is closed, would be welcomed by many vehicle manufacturers, vehicle owners, and service station operators.
According to the present invention, a filler neck closure assembly is provided for a vehicle fuel tank filler neck. The filler neck closure assembly includes a housing configured to mount in the filler neck and formed to include a sealing surface. A pressure-relief valve is mounted for movement in the housing and formed to include a nozzle-receiving portion and a sealing portion. The nozzle-receiving portion is formed to include an inner nozzle-receiving opening that receives a pump nozzle during refueling of the fuel tank. The sealing portion normally engages the sealing surface formed in the housing.
The sealing portion of the pressure-relief valve is movable relative to the housing between a closure-sealing position and a pressure-relief position in response to changing pressure conditions in the filler neck so as to relieve excess fuel vapor pressure that develops from time to time in the filler neck. Normally, the filler neck pressure is below a predetermined maximum pressure and the sealing portion of the pressure-relief valve is retained in the closure-sealing position sealingly engaging the sealing surface to block discharge of liquid fuel and fuel vapor from the filler neck to the atmosphere past the pressure-relief valve. However, when filler neck pressure exceeds the predetermined maximum pressure, the sealing portion is moved by such high pressure away from the sealing surface in the housing to the pressure-relief position to define a venting opening between the housing and the pressure-relief valve. This allows pressurized fuel vapor to vent from the fuel tank to the atmosphere through the vent opening.
The pressure-relief valve is configured so that the nozzle-receiving portion formed therein moves along with the sealing portion formed therein when the sealing portion moves between the closure-sealing position and the nozzle-receiving position to vent pressurized fuel vapor from the filler neck to the atmosphere. Illustratively, the sealing portion is arranged to surround the nozzle-receiving portion.
In preferred embodiments, the filler neck closure assembly is installed in the filler neck of a vehicle fuel tank. The filler neck closure assembly is a xe2x80x9ccapless systemxe2x80x9d because it does not include a traditional fuel cap that is separate and removable from the filler neck. Significantly, the filler neck closure assembly is configured to allow an attendant or a robotic mechanism to insert a fuel-dispensing pump nozzle into the filler neck during refueling of the fuel tank without first removing a separate fuel cap from the mouth of the filler neck. In addition, after refueling is completed and the pump nozzle is withdrawn, the closure assembly automatically closes the filler neck so that it is unnecessary for an attendant or a robotic mechanism to install a separate fuel cap on the filler neck to close the mouth of the filler neck.
Vehicles having fuel tanks are often operated in environments in which fuel in the fuel tank experiences temperature fluctuations resulting in fuel vapor pressure fluctuations in the fuel tank. The pressure-relief valve is mounted in the housing to relieve unwanted fuel vapor pressure in the fuel tank in excess of a predetermined maximum pressure that can develop, for example, during operation of a vehicle in hot environments.
Illustratively, the pressure-relief valve in accordance with the present invention is a slidable, spring-loaded disk mounted at an outer end of the filler neck adjacent to the mouth of the filler neck. In addition, a vacuum-relief valve is provided in the housing to relieve unwanted vacuum in the fuel tank. The vacuum-relief valve functions to admit air from the atmosphere into the filler neck so as to increase tank pressure when tank pressure is less than a predetermined minimum pressure. Vacuum conditions can develop in a fuel tank during the cool-down of a vehicle that can occur, for example, at night. Illustratively, the vacuum-relief valve is a spring-loaded valve pivotably mounted on the pressure-relief valve.
The pressure-relief valve is formed to include a central opening that is normally closed by the pivotable spring-loaded vacuum-relief valve mounted on the pressure-relief valve. During refueling, an attendant or robotic mechanism passes a pump nozzle through the central opening formed in the pressure-relief valve and pivots the vacuum-relief valve to an opened position so that the pump nozzle can be used to discharge liquid fuel into the fuel tank filler neck without disrupting the position and filler-neck closing function of the pressure-relief valve. Normally, the sealing portion of the pressure-relief valve is urged by a spring to its closure-sealing position closing the filler neck during refueling. Advantageously, the pump nozzle can pass through the central opening formed in the nozzle-receiving portion of the pressure-relief valve without disturbing or moving the surrounding sealing portion of the pressure-relief valve.
During fuel tank cool-down, excessive vacuum in the fuel tank and filler neck creates a suction force in the filler neck sufficient to pivot the spring-loaded vacuum-relief valve away from is seat against the pressure-relief valve to an opened position. Such automatic xe2x80x9copeningxe2x80x9d of the vacuum-relief valve functions to allow a flow of air from the atmosphere into the fuel tank filler neck through the central opening formed in the pressure-relief valve, thereby relieving the unwanted low tank and filler neck pressure automatically. This inflow of atmospheric air can occur even though the pressure-relief valve remains in a filler neck-closing position.
In preferred embodiments, the closure assembly includes an outer shell connected to the housing and positioned to lie adjacent to an outer side of the slidable spring-loaded pressure-relief valve. The outer shell has a front wall that defines a nozzle-guiding surface and that is formed to include a nozzle-receiving opening in fluid communication with the central opening formed in the adjacent pressure-relief valve. The front wall is generally funnel-shaped so that a pump nozzle engaging the nozzle-guiding surface defined by front wall and advancing into the closure assembly during refueling of the fuel tank is guided radially inwardly toward the nozzle-receiving opening formed in the outer shell. Advantageously, the nozzle-guiding surface on the front wall is helpful both to attendants manually guiding pump nozzles into the closure assembly and to robotic refueling systems automatically guiding pump nozzles into the closure assembly. In addition, the front wall provides a seating surface to accommodate fuel vapor recovery nozzle assemblies that include external fuel vapor recovery boots.
The closure assembly is easily installed into the filler neck of the fuel tank at the time of vehicle manufacture or repair. The installer simply grasps the outer shell of the closure assembly and places a threaded inner end of the housing into engagement with the threaded filler neck. Rotation of the outer shell by the installer in a clockwise closure-advancing direction brings the threads on the housing into interlocking engagement with the threads in the filler neck. Continued rotation of the outer shell causes the outer shell and the housing unit to be drawn into the filler neck. Once the housing is properly seated in the filler neck, the outer shell can be rotated or indexed relative to the seated housing to assume a corrected installation orientation and position on the filler neck.
An annular sealing gasket is provided on an outer portion of the housing. As the installer rotates the outer shell and housing unit in the closure-advancing direction, the closure assembly advances to a tight seated position in the filler neck in which the sealing gasket is trapped between the filler neck and the housing to establish a liquid fuel and fuel vapor seal therebetween.
Advantageously, the closure assembly is designed and constructed to protect the sealing gasket from damage that might be caused by over tightening the housing in the filler neck. The closure assembly is configured to divert excessive closure-advancing torque that an installer might apply to the outer shell away from the housing and the sealing gasket.
The torque-limiting mechanism interposed between the outer shell and the housing allows torque applied to the outer shell below a predetermined maximum torque to be transmitted from the outer shell to the housing and torque applied to the outer shell above the predetermined maximum torque to be diverted away from the housing and the sealing gasket trapped between the housing and the filler neck. The torque-limiting mechanism causes the outer shell to rotate independently of the housing when the torque applied to the outer shell exceeds the predetermined maximum torque, for example, when the installer continues to rotate the outer shell after the closure assembly has advanced to the tight seated position in the filler neck, rather than transmitting the torque from the outer shell to the housing. The independent rotation of the outer shell relative to the housing protects the sealing gasket while also permitting the installer to orient the outer shell in a proper radial installation position relative to the filler neck without affecting or damaging the seal formed between the filler neck and the housing.
Advantageously, the radial orientation of the central opening of the pressure-relief valve relative to the outer shell is fixed by a spline appended to the pressure-relief valve and mounted in an opening of the outer shell. The spline cooperates with the outer shell to radially fix the pressure-relief valve relative to the outer shell and to cause the pressure-relief valve to rotate relative to the housing in response to rotation of the outer shell relative to the housing when the outer shell is rotated or indexed to assume the corrected installation orientation and position on the filler neck.
Additionally, a frangible connection between the outer shell and the housing is designed and configured to enhance and control breakage of the closure assembly between the outer shell and the housing in a manner that is designed to leave the filler neck closed during an impact to the closure assembly. A flange that connects the housing and the outer shell has a frangible section to enhance breakage of the flange relative to the housing. The closure assembly is configured so that the filler neck will remain closed after the separation of the outer shell and the flange from the housing.
Also in preferred embodiments, various components of the closure assembly are decorated with selected codes, adornments, and/or patterns to facilitate detection of the filler neck and closure assembly. For example, the outer shell and a flapper door included in the vacuum-relief valve can cooperate to provide information useful for visual detection of the location of the filler neck and closure assembly. The outer shell can be made from a material having a light color and the flapper door can be made from a material having a dark color. Together, the outer shell and flapper door, which includes a flat plate that is visible behind the nozzle-receiving opening, can present a xe2x80x9cbulls-eyexe2x80x9d pattern that is easily recognizable by an attendant guiding a pump nozzle into the closure assembly.
Some robotic refueling systems use a filler neck detection system to locate the filler neck for the robotic refueling system prior to docking the pump nozzle in the closure assembly. In these instances, codes, adornments, and/or patterns of the type described can provide docking verification information that can be used by the robotic refueling system.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.